Method and composition for coating pre-sized paper with a mixture of a polyacid and a polybase

Abstract

The present invention features coating compositions and methods for improving the quality of images printed on a paper substrate. The novel coating compositions contain a coating agent comprising a mixture of a polyacid and a polybase. When applied to a sized paper substrate, the coating compositions provide a coated paper substrate that provides high quality printed images when printed with an ink containing a reactive dye having ionizable and / or nucleophilic groups capable of reacting with the coating agent. Images printed on a paper substrate coated with the coating composition of the invention are bleed-resistant, water-resistant (e.g., water-fast), and / or are characterized by an enhanced chroma and hue.

Description

The present invention relates generally to the production of coated paper, and more particularly relates to a novel paper coating process and novel compositions useful in conjunction therewith.As printing technology advances, paper manufacturers are faced with the increasingly rigorous demands of their customers for high quality paper that is economically attractive. For example, there is a keen demand for papers that meet high quality standards with respect to brightness, opacity, and dry and / or wet strength, and that, upon printing with any of a wide range of colorants, provide a water-resistant printed image. The customer further demands that such papers be amenable to use with a variety of printing techniques, including not only conventional printing techniques, but also "impact free" printing techniques such as inkjet printing (particularly colored inkjet printing), laser printing, photocopying, and the like.In response, paper manufacturers have attempted to meet their customer...

Examples

example 1

MIXING PROCEDURES FOR ACID-BASE, NO-STARCH SYSTEMS

An exemplary acid-base coating formulation was prepared according to the following:

The acid, base, and stearic maleic anhydride (SMA) were mixed together with constant stirring in an appropriate amount of water. The resulting mixture was rather thick. However, upon addition of ammonia, the mixture became less viscous. The polymer (AR74) and a drop of defoamer were then blended in and the resulting mixture was stirred for another half hour before coating onto a paper substrate.

example 2

POLYACID / POLYBASE COATING COMPOSITIONS

The following table summarizes exemplary coating compositions in accordance with the invention, wherein the coating agent is mixture of a polyacid and a polybase. Each of the representative formulations was effective to produce a coated paper substrate having the beneficial features described herein, i.e., with respect to bleeding, wicking and water-fastness.

The present invention relates generally to the production of coated paper, and more particularly relates to a novel paper coating process and novel compositions useful in conjunction therewith.As printing technology advances, paper manufacturers are faced with the increasingly rigorous demands of their customers for high quality paper that is economically attractive. For example, there is a keen demand for papers that meet high quality standards with respect to brightness, opacity, and dry and / or wet strength, and that, upon printing with any of a wide range of colorants, provide a water-resistant printed image. The customer further demands that such papers be amenable to use with a variety of printing techniques, including not only conventional printing techniques, but also "impact free" printing techniques such as inkjet printing (particularly colored inkjet printing), laser printing, photocopying, and the like.In response, paper manufacturers have attempted to meet their customer...

Examples

example 1

MIXING PROCEDURES FOR ACID-BASE, NO-STARCH SYSTEMS

An exemplary acid-base coating formulation was prepared according to the following:

The acid, base, and stearic maleic anhydride (SMA) were mixed together with constant stirring in an appropriate amount of water. The resulting mixture was rather thick. However, upon addition of ammonia, the mixture became less viscous. The polymer (AR74) and a drop of defoamer were then blended in and the resulting mixture was stirred for another half hour before coating onto a paper substrate.

example 2

POLYACID / POLYBASE COATING COMPOSITIONS

The following table summarizes exemplary coating compositions in accordance with the invention, wherein the coating agent is mixture of a polyacid and a polybase. Each of the representative formulations was effective to produce a coated paper substrate having the beneficial features described herein, i.e., with respect to bleeding, wicking and water-fastness.